In the past there have been numerous types of knives and this invention is of a knife which is provided with a blade which is protectively within the handle so that, when used on an inflatable aircraft raft, for example, the blade will not inadvertently puncture the raft in use. Such a knife is important on a raft because when it is thrown, for example, from an aircraft in an emergency situation, such as a forced landing at sea, the raft must be connected to the aircraft so that it does not float away. On the other hand, if the aircraft is to sink, then the tether must be cut so that the raft does not go down with the aircraft. For this reason a knife is important to be among the emergency equipment on an inflatable raft used by an aircraft. This invention is of a knife which is configured, constructed and adapted for such a purpose.